President Barack Obama speaks at a campaign event Thursday at the Prime Osborn Convention Center in Jacksonville, Fla. Obama is spending two days in Florida campaigning. (ASSOCIATED PRESS / Susan Walsh)

WEST PALM BEACH, Fla. (AP) — Wooing Florida voters, President Barack Obama warned Thursday that Republican challenger Mitt Romney would gut his health care reform law and turn Medicare into a voucher program, driving up costs for the elderly on fixed incomes. Romney, firing away near his Boston home base, accused Obama of caring only about saving his own job — not the jobs of Americans.

In the daily war of words in an up-for-grabs presidential contest, health care politics took top billing as Obama opened two days of campaigning in Florida, the largest and most coveted of the nation’s Election Day toss-up states. Obama could see his chances for another term seriously damaged if Romney prevails here.

For his part, Romney, in hastily arranged remarks to reporters near Boston, kept the focus on the sluggish economic recovery under Obama’s watch. He cited new government figures showing that the number of American seeking unemployment benefits rose by 34,000 last week, a figure that may have been skewed higher by seasonal factors.

Both candidates were pouring most of their money and attention into the collection of fewer than 10 states expected to decide the election. First lady Michelle Obama launched a new effort to rally supporters behind her husband, trying to light a fire by saying the whole race could “come down to just a few votes per precinct in key states.”

Nowhere is the campaign potentially more pivotal than in Florida, which decided the 2000 election and remains the ultimate swing state. With a large pool of retired voters, Medicare has been used by both parties to rally support from seniors in Florida and elsewhere, mostly by warning that the other party had in mind changes that would curb the national insurance program for older Americans.

Obama sought to broaden his attack on Romney’s support for a House Republican plan that would shift Medicare from a fee-for-service program into one where future retirees buy insurance using subsidies. Republicans say it would introduce competition and give seniors more choices, but it is closely watched in Florida, where about half of the 2008 electorate was age 50 and older.

“He plans to turn Medicare into a voucher program,” Obama said at West Palm Beach’s Century Village, home to thousands of Democratic retirees from New York, New Jersey and elsewhere. “If the voucher isn’t worth what it takes to buy health insurance in the private marketplace, you’re out of luck. You’ve got to make up the difference. You’re on your own.”

Romney would provide subsidies — Democrats call them vouchers — to help future retirees buy private insurance, or let them have the option of traditional Medicare, with a gradually increasing age to qualify for benefits. Current retirees would not be affected.

“(Obama) has offered no serious plan of his own to save Medicare and is content to use it as nothing more than a political issue,” said Lanhee Chen, the Romney campaign’s policy director.

Romney has criticized Obama’s health care law, noting that Obama calls for $500 billion in cuts to Medicare. But Obama would make most of those cuts by reducing payments to service providers such as hospitals and nursing homes, not beneficiaries.

Under the health care law, Medicare coverage would improve for those with high prescription costs, and would require no copayments for preventive care.

During stops in Jacksonville and in West Palm Beach, Obama jumped on Romney’s opposition to his health care reform law, which was recently upheld by the Supreme Court. He said the former Massachusetts governor’s approach would force more than 200,000 Floridians pay more for their prescription drugs.

“It’s wrong to ask you to pay more for Medicare so that people who are doing well right now get even more,” Obama told seniors at Century Village. “That’s no way to reduce the deficit. We shouldn’t be squeezing more money out of seniors.”

For Obama, who has frequently struggled to build support among elderly voters, the health care pitch was directed at retirees in Florida, home to the all-important prize of 29 electoral votes. Even in winning here in 2008, Obama lost to John McCain among voters 65 and older.

Back in Massachusetts, Romney again criticized Obama for not having met with his advisory jobs council in six months while holding more than 100 fundraisers in that time. White House spokesman Jay Carney had said Wednesday that the president gets advice from the council all the time but also has “got a lot on his plate.”

The White House sought to counter that line of attack by showing presidential action. Obama’s administration announced it was speeding up expansion projects at five major U.S. ports, including two in politically important Florida. Carney made a point to note that the idea came from Obama’s jobs council.

In speaking to a largely Jewish audience in West Palm Beach, Obama said the nation was “heartbroken” over the terrorist attack launched against Israeli tourists in Bulgaria and said his administration hadn’t “just preserved the unbreakable bond with Israel, we have strengthened it.”

As Obama stuck to his economic message, his campaign kept up its aggressive attempt to raise doubts about Romney’s trustworthiness. Obama and his surrogates have been pushing Romney to release more than two years of tax returns. Some members of Romney’s party have agreed, although others say the idea is a distraction.

“We’ve given all you people need to know and understand about our financial situation and about how we live our life,” Romney’s wife, Ann, told ABC News in an interview broadcast Thursday.

In a separate interview aired Thursday on WTOL-TV in Toledo, Ohio, Romney said one reason not to release more of his returns was that “the Democratic Party and the opposition has all these people that comb through and try and find anything they can to distract from the issues people care about, oftentimes in a dishonest way.”